For conventional biochemical analyzers, a protective cover of the analyzer needs to be opened or even removed so to remove the lid for the sample disk when loading a sample. After the sample is loaded, the sample disk lid and the protective cover are returned to their respective original positions. In this conventional biochemical analyzer, operations may be tedious. In addition, after the lid for the sample disk has been opened or removed, the sample disk may still be rotating or may start to rotate. In this case, loading and unloading the sample may pose some potentially dangerous conditions.